The Importance of Air Conditioner Maintenance

Regular cleaning and maintenance of your air conditioning systems keeps the air quality in your building at optimal levels. Not only does dirt, dust mites, and other allergens harm your health (resulting in allergies, hay fever and other respiratory conditions), but regular cleaning and maintenance can help reduce the risk of these contaminants from the air conditioning systems and spreading through your building.

There are a variety of air conditioning systems used in residential apartment buildings. These include stand-alone split-system or window-mounted units in individual apartments, cooling towers and chillers that provide air to apartments through ducting or cooling towers that feed separate air conditioning units in plant rooms on each floor or in each apartment. Air-cooled air-conditioning systems are also widely used.

To provide a healthy and pleasant environment for residents, it is imperative that preventative maintenance and testing is performed in accordance with manufactures’ specifications (please refer to ‘Important features of maintenance procedures’ towards the end of article.

There are indoor air quality and subsequent health risks associated with all types of air-conditioning systems, but the health risks are greatest with systems that use cooling towers. There has been a breakout from Legionnaire’s disease in recent years that have been traced to cooling towers, stressing the importance of maintenance and testing1. While most people recover from the disease, it is occasionally fatal.

However, the onus generally falls on building owners and managers, who should also obtain expert advice on the risks associated with other types of air conditioning systems.

Legionnaire’s disease is an infection caused by exposure to Legionella bacteria, which can be very common and relatively safe at low levels in our environment. However, air conditioning cooling towers can provide a warm, supportive environment, conducive to growth well beyond normal environmental levels.

Often cases of Legionnaires’ disease can be traced to exposure to mists or airborne water droplets containing Legionella bacteria2. Such mists can come from air-conditioning cooling towers. The disease is not transmitted between people.

Risk of infection is a combination of the amount of Legionella bacteria to which the body is exposed and the resistance of the individual to the bacteria. The risk is increased for those who are immunocompromised2. Diabetics, those suffering from chronic lung, heart or kidney disease, aged persons, smokers, and heavy drinkers also have increased risk.

The key to reducing the risk of contracting Legionnaires’ disease is to minimise the risk of exposure to Legionella bacteria, which can be done by managing air conditioning cooling towers in apartment buildings (please refer to ‘Important features of maintenance procedures’ at the end of article.

Building managers must ensure there is a formal, enforceable agreement with contractors that outline maintenance, testing procedures and ensuring compliance with AS/NZS 3666 or other equivalent standards. The contract should include timing, content and format of maintenance reports with respect to Legionella bacteria, consistent with that contained in AS/NZS 3896.

Management should gain expert advice on the type of air-conditioning plant in use, its age, method of operation and any features likely to affect production and dispersal of Legionella bacteria. The risk may vary according to age, design and manufacturer.

Building management should obtain regular reports on all testing and any treatments undertaken by a maintenance contractor as part of their routine or seasonal maintenance.  Local councils or other regulatory bodies may also require a copy of the testing reports.

Dosing

This involves adding biocides to control microbial growth, fouling, scaling and corrosion, which should achieve zero Legionella growth. Dosing should be a regular procedure, although dosing level and frequency may vary with seasonal changes.

Cleaning

This should be done at least once every three months, particularly before upcoming warmer weather or after a prolonged shut down.

Testing

This determines if the maintenance procedures are effective. Testing requirements vary between states, however the industry standard generally conducts monthly testing and it is highly recommended that this be adopted as the minimum period between tests.

• Reports should be made in accordance with AS/NZS 3896 and the laboratory testing should be NATA registered and should also be AS/NZS ISO 9002 accredited for their management system.
• The various standards, AS 1668.2, AS/NZS 3666.1, AS/NZS 3666.2 and AS/NZS 3666.3, sets out specific actions required when tests indicate specific bacterial levels have been exceeded. When exceeded, building managers should satisfy themselves that appropriate investigation, review and remedial action has been undertaken.
• There are differing notification procedures between states and local government areas and building management should be aware of which authorities should be contacted if high levels of Legionella have been detected.